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2018-03-16
ServiceSystemCtl.txt.txt



以前只要
service httpd start
/etc/init.d/httpd start
chkconfig --list
chkconfig httpd on

就可操作服務的生死
服務不再是由 init 負責，而是 systemd，而傳統的 runlevel 也改為 target
雖然說以上部份在 CentOS7 還是可以使用啦，只是要漸漸習慣使用 systemctl 才行
systemctl 已不把啟動檔放在 /etc/rc.d/init.d/ 裡面
改放在 /etc/systemd/system 裡，這裡也只放已被 enable ，它是從 /usr/lib/systemd/system/ 這裡 link 過來的
所以使用上一定有不習慣

啟動
systemctl start httpd
systemctl start mysql
systemctl start mariadb

停止
systemctl stop httpd
systemctl stop mysql
systemctl stop mariadb

開機後自動啟動
systemctl enable httpd

開機後自動停用
systemctl disable httpd

服務狀態
systemctl status httpd
service vsftpd status  --> redirection to /bin/systemctl status vsftpd.service

列出全部服務
systemctl list-unit-files

列出服務，正在跑的
systemctl list-units --type service | grep running

顯示目前系統預設運作層級
systemctl get-default

如果顯示 multi-user.target，就以前的 runlevel 3
而 graphical.target 為 runlevel 5

切換運作層級至文字模式 runlevel 3
systemctl isolate multi-user.target

設定開機啟動至文字模式 runlevel 3
systemctl set-default multi-user.target

重啟service
service vsftpd restart
systemctl restart httpd.service
systemctl restart firewalld
systemctl restart mysqld.service 

其它
systemctl restart httpd.service
systemctl reload httpd.service
systemctl kill httpd.service
systemctl show httpd.service

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啟動服務
sudo systemctl restart vsftpd

開機時自動啟動服務
sudo systemctl enable vsftpd